function mostrar(nombreCapa)
    {
        document.getElementById(nombreCapa).style.visibility="visible";
        nombreCapa.style.visibility="visible";
    }

function ocultar(nombreCapa)
    {
        document.getElementById(nombreCapa).style.visibility="hidden";
        nombreCapa.style.visibility="hidden";
    }

function rdm()
{
    var myWidth = 0, myHeight = 0;
    if( typeof( window.innerWidth ) == 'number' )
    {
        //Non-IE
        myWidth = window.innerWidth;
        myHeight = window.innerHeight;
    }
    else
        if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) )
        {
            //IE 6+ in 'standards compliant mode'
            myWidth = document.documentElement.clientWidth;
            myHeight = document.documentElement.clientHeight;
        }
        else
            if( document.body && ( document.body.clientWidth || document.body.clientHeight ) )
            {
            //IE 4 compatible
            myWidth = document.body.clientWidth;
            myHeight = document.body.clientHeight;
            }

        bleft.style.height=(myHeight-240) + "px";
        repro.style.height=(myHeight-240) + "px";
       <!-- main.style.height=winheight + "px"; -->
}